Year: 2020
Type: article
Abstract: We evaluate theoretically the thermoelectric efficiency of the layered perovskite ${\mathrm{Sr}}_{2}{\mathrm{Nb}}_{2}{\mathrm{O}}_{7}$ via calculations of the electronic structure and transport coefficients within density-functional theory and Bloch-Boltzmann relaxation-time transport theory. The predicted figure-of-merit tensor $ZT$, computed with energy-, chemical potential--, and temperature-dependent relaxation times, has one component increasing monotonically from around 0.4 at room temperature to 2.4 at 1250 K at an optimal carrier density of around $2\ifmmode\times\else\texttimes\fi{}{10}^{20}\phantom{\rule{0.28em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$, while the other components are small. The Seebeck coefficient is about 250 to 300 $\ensuremath{\mu}\mathrm{V}$/K at optimal doping and reaches 800 $\ensuremath{\mu}\mathrm{V}$/K at lower doping. We provide a python code implementing various approximations to the energy-dependent relaxation-time transport, which can be used to address different systems with an appropriate choice of material parameters.
Source: Physical Review Materials
Authors: Giulio Casu, Andrea Bosin, Vincenzo Fiorentini
Institution: University of Cagliari
Language: Latvian
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3045132999